<template>
    <view class="uni-pagination">
        <view class="uni-pagination__total">
            共 {{total}} 条
        </view>
        <view class="uni-pagination__btn" :class="currentIndex === 1 ? 'uni-pagination--disabled' : 'uni-pagination--enabled'"
            :hover-class="currentIndex === 1 ? '' : 'uni-pagination--hover'" :hover-start-time="20" :hover-stay-time="70"
            @click="clickLeft">
            <template v-if="showIcon===true || showIcon === 'true'">
                <uni-icons color="#666" size="16" type="arrowleft" />
            </template>
            <template v-else><text class="uni-pagination__child-btn">{{ prevText }}</text></template>
        </view>
        <view class="uni-pagination__num">
            <view class="uni-pagination__num-current">
                <!-- <text class="uni-pagination__num-current-text" style="color:#007aff">{{ currentIndex }}</text><text
                    class="uni-pagination__num-current-text">/{{ maxPage || 0 }}</text>
 -->
                <view v-for="(item,index) in paper" :key="index" :class="{'page--active':item === currentIndex}" class="uni-pagination__num-tag tag--active"
                    @click.top="selectPage(item,index)">
                    <text> {{item}}</text>
                </view>
                <!-- <view class="uni-pagination__num-tag"><text class="uni-pagination__child-btn">
                        <<</text> </view> <view class="uni-pagination__num-tag">3</view>
                <view class="uni-pagination__num-tag">4</view>
                <view class="uni-pagination__num-tag">5</view>
                <view class="uni-pagination__num-tag">6</view>
                <view class="uni-pagination__num-tag"><text class="uni-pagination__child-btn">>></text></view>
                <view class="uni-pagination__num-tag">8</view> -->
            </view>
        </view>
        <view class="uni-pagination__btn" :class="currentIndex >= maxPage ? 'uni-pagination--disabled' : 'uni-pagination--enabled'"
            :hover-class="currentIndex === maxPage ? '' : 'uni-pagination--hover'" :hover-start-time="20"
            :hover-stay-time="70" @click="clickRight">
            <template v-if="showIcon===true || showIcon === 'true'">
                <uni-icons color="#666" size="16" type="arrowright" />
            </template>
            <template v-else><text class="uni-pagination__child-btn">{{ nextText }}</text></template>
        </view>
    </view>
</template>

<script>
import uniIcons from '../uni-icons/uni-icons.vue'

/**
     * Pagination 分页器
     * @description 分页器组件，用于展示页码、请求数据等
     * @tutorial https://ext.dcloud.net.cn/plugin?id=32
     * @property {String} prevText 左侧按钮文字
     * @property {String} nextText 右侧按钮文字
     * @property {Number} current 当前页
     * @property {Number} total 数据总量
     * @property {Number} pageSize 每页数据量
     * @property {Number} showIcon = [true|false] 是否以 icon 形式展示按钮
     * @event {Function} change 点击页码按钮时触发 ,e={type,current} current为当前页，type值为：next/prev，表示点击的是上一页还是下一个
     */

export default {
  name: 'UniPagination',
  components: {
    uniIcons
  },
  props: {
    value: {
      type: [Number, String],
      default: 1
    },
    prevText: {
      type: String,
      default: '上一页'
    },
    nextText: {
      type: String,
      default: '下一页'
    },
    current: {
      type: [Number, String],
      default: 1
    },
    total: { // 数据总量
      type: [Number, String],
      default: 0
    },
    pageSize: { // 每页数据量
      type: [Number, String],
      default: 10
    },
    showIcon: { // 是否以 icon 形式展示按钮
      type: [Boolean, String],
      default: false
    },
    pagerCount: {
      type: Number,
      default: 7
    }
  },
  data () {
    return {
      currentIndex: 1,
      paperData: []
    }
  },
  computed: {
    maxPage () {
      let maxPage = 1
      const total = Number(this.total)
      const pageSize = Number(this.pageSize)
      if (total && pageSize) {
        maxPage = Math.ceil(total / pageSize)
      }
      return maxPage
    },
    paper () {
      const num = this.currentIndex
      // TODO 最大页数
      const pagerCount = this.pagerCount
      // const total = 181
      const total = this.total
      const pageSize = this.pageSize
      const totalArr = []
      const showPagerArr = []
      const pagerNum = Math.ceil(total / pageSize)
      for (let i = 0; i < pagerNum; i++) {
        totalArr.push(i + 1)
      }
      showPagerArr.push(1)
      const totalNum = totalArr[totalArr.length - (pagerCount + 1) / 2]
      totalArr.forEach((item, index) => {
        if ((pagerCount + 1) / 2 >= num) {
          if (item < pagerCount + 1 && item > 1) {
            showPagerArr.push(item)
          }
        } else if (num + 2 <= totalNum) {
          if (item > (num - (pagerCount + 1) / 2) && item < (num + (pagerCount + 1) / 2)) {
            showPagerArr.push(item)
          }
        } else {
          if ((item > num - (pagerCount + 1) / 2 || pagerNum - pagerCount < item) && item <
                            totalArr[totalArr.length - 1]) {
            showPagerArr.push(item)
          }
        }
      })
      if (pagerNum > pagerCount) {
        if ((pagerCount + 1) / 2 >= num) {
          showPagerArr[showPagerArr.length - 1] = '...'
        } else if (num + 2 <= totalNum) {
          showPagerArr[1] = '...'
          showPagerArr[showPagerArr.length - 1] = '...'
        } else {
          showPagerArr[1] = '...'
        }
        showPagerArr.push(totalArr[totalArr.length - 1])
      } else {
        if ((pagerCount + 1) / 2 >= num) {} else if (num + 2 <= totalNum) {} else {
          showPagerArr.shift()
          showPagerArr.push(totalArr[totalArr.length - 1])
        }
      }

      return showPagerArr
    }
  },
  watch: {
    current (val) {
      this.currentIndex = val
    },
    value (val) {
      if (val < 1) {
        this.currentIndex = 1
      } else {
        this.currentIndex = val
      }
    }
  },
  created () {
    this.currentIndex = +this.value
  },
  methods: {
    // 选择标签
    selectPage (e, index) {
      if (parseInt(e)) {
        this.currentIndex = e
        this.change('current')
      } else {
        const pagerNum = Math.ceil(this.total / this.pageSize)
        // let pagerNum = Math.ceil(181 / this.pageSize)
        // 上一页
        if (index <= 1) {
          if (this.currentIndex - 5 > 1) {
            this.currentIndex -= 5
          } else {
            this.currentIndex = 1
          }
          return
        }
        // 下一页
        if (index >= 6) {
          if (this.currentIndex + 5 > pagerNum) {
            this.currentIndex = pagerNum
          } else {
            this.currentIndex += 5
          }
        }
      }
    },
    clickLeft () {
      if (Number(this.currentIndex) === 1) {
        return
      }
      this.currentIndex -= 1
      this.change('prev')
    },
    clickRight () {
      if (Number(this.currentIndex) >= this.maxPage) {
        return
      }
      this.currentIndex += 1
      this.change('next')
    },
    change (e) {
      this.$emit('input', this.currentIndex)
      this.$emit('change', {
        type: e,
        current: this.currentIndex
      })
    }
  }
}
</script>

<style lang="scss" scoped>
    .uni-pagination {
        /* #ifndef APP-NVUE */
        display: flex;
        /* #endif */
        position: relative;
        overflow: hidden;
        flex-direction: row;
        justify-content: center;
        align-items: center;
    }

    .uni-pagination__total {
        font-size: 14px;
        color: #999;
        margin-right: 15px;
    }

    .uni-pagination__btn {
        /* #ifndef APP-NVUE */
        display: flex;
        cursor: pointer;
        /* #endif */
        width: 30px;
        height: 30px;
        line-height: 30px;
        font-size: $uni-font-size-base;
        position: relative;
        background-color: $uni-bg-color-grey;
        flex-direction: row;
        justify-content: center;
        align-items: center;
        text-align: center;
        border-width: 1px;
        border-style: solid;
        border-color: $uni-border-color;
    }

    .uni-pagination__child-btn {
        /* #ifndef APP-NVUE */
        display: flex;
        /* #endif */
        font-size: $uni-font-size-base;
        position: relative;
        flex-direction: row;
        justify-content: center;
        align-items: center;
        text-align: center;
    }

    .uni-pagination__num {
        /* #ifndef APP-NVUE */
        display: flex;
        /* #endif */
        flex: 1;
        flex-direction: row;
        justify-content: center;
        align-items: center;
        height: 30px;
        line-height: 30px;
        font-size: $uni-font-size-base;
        color: $uni-text-color;
        margin: 0 5px;
    }

    .uni-pagination__num-tag {
        cursor: pointer;
        margin: 0 5px;
        height: 30px;
        min-width: 30px;
        text-align: center;
        line-height: 30px;
        // border: 1px red solid;
        color: #666;
        border-width: 1px;
        border-style: solid;
        border-color: $uni-border-color;
    }

    .uni-pagination__num-current {
        /* #ifndef APP-NVUE */
        display: flex;
        /* #endif */
        flex-direction: row;
    }

    .uni-pagination__num-current-text {
        font-size: 15px;
    }

    .uni-pagination--enabled {
        color: #333333;
        opacity: 1;
    }

    .uni-pagination--disabled {
        opacity: 0.3;
    }

    .uni-pagination--hover {
        color: rgba(0, 0, 0, .6);
        background-color: $uni-bg-color-hover;
    }

    .tag--active:hover {
        color: #007aff;
    }

    .page--active {
        color: #fff;
        background-color: #007aff
    }

    .page--active:hover {
        color: #fff;
    }
</style>
